1. Field of the Invention
The present invention relates to an information processing device such as a facsimile device or personal computer or the like and to an external device such as a scanner or printer or the like which is capable of connecting with the information processing device.
2. Description of the Related Art
With the recent development of an information society, the ways information processing devices are used have increased greatly. However, realizing a single information processing device that is able to cope with all such demands would be expensive. Accordingly, various external devices are connected as necessary to a device that is provided with basic functions.
Thus, if a facsimile is used as an example of an information processing device, a modem for use with multiple lines, a scanner or a printer or the like are all examples of external devices. Methods for connection of these external devices to the information processing device are, for example, providing a connector for connecting the external devices to the information processing device, or connecting the external devices by a daisy chain method using a special interface board of such as SCSI (Small Computer System Interface) format.
However, when connectors are used, if a plurality of external devices are to be connected to the information processing device, it is necessary to arrange a plurality of connectors on that information processing device. Moreover, the construction for handling the interface with the external devices becomes complicated in response to the increase in number of connectors. In this way, a structure for controlling a plurality of external devices must be pre-provided in the information processing device even if no external devices are connected to the information processing device, causing increased production costs. Furthermore, if the number of external devices connected to the connector increases, the load on the CPU (Central Processing Unit) of the information processing device that control all these connectors increases.
Yet further, using a method utilizing a special interface board such as an SCSI format or the like, it is necessary to arrange this interface board on the information processing device and external device and to perform communication between the information processing device and external device in accordance with a specific communication protocol. Moreover, it is necessary to change the specifications of the interface board arranged in the information processing device according to the number of external devices connected to the information processing device and what kind of device they are. As a result, such arrangement of the information processing device and external device as above not only become costly but there are limitations on communication procedures as it is necessary to perform communication in accordance with specific communication protocols, decreasing the utility of the device.